Gene therapy may provide a new therapeutic approach to inhibition of HIV- 1 infection of patient cells. Insertion of genes which inhibition HIV-1 replication into T cells or their progenitors, the hematopoietic stem cells (HSC), may lead to production of cells which are resistant to HIV-1 replication, prolonging immune function. The central hypothesis of this proposal is that the M10 trans-dominant mutant rev gene can be inserted into HSC from the bone marrow or umbilical cord blood cells of children infected with HIV-1 leading to the production of mature T cells and monocytes which express the M10 gene and are thereby resistant to HIV-1 replication. Potentially, adverse affects from HIV-1 infection may make either the hematopoietic cells or stromal cells from patients sub-optimal for these purposes. We will, therefore, first perform pre-clinical studies to demonstrate that the M10 trans-dominant gene may be inserted and expressed in CD34+ cells isolated from the bone marrow of HIV-1 infected patients. We will also perform collaborative studies to analyze new methods of targeted gene delivery and expression with hematopoietic cells. These studies will then lead to a clinical trial involving transduction with the M10 gene of CD34+ cells from pediatric patients with HIV-1 infection. We will transduce either bone marrow samples from HIV-1 infected children or umbilical cord blood cells from newborns identified with HIV-1 infection at birth. For each patient, half of the cells will be transduced with the M10 gene and half with a frame-shifted inactive version of M10. The transduced cells will be re-infused into the patients intravenously. We will then follow the patients to detect the development of circulating T cells (especially CD4+ cells) containing and expressing the M10 gene. We will determine whether expression of functional M10 confers a protective survival advantage to transduced cells and whether this has a beneficial effect on the expected clinical parameters of HIV infection. In all, these studies will critically examine the potential of gene therapy with the M10 trans-dominant gene inserted into hematopoietic stem cells to confer protection from HIV-1.